Week Five - Repeated Measures ANOVA

Question 1

What is a repeated measures ANOVA?

Answer 1

Where same subjects are tested repeatedly

Question 2

Advantages of RMA?

Answer 2

Economy of subjects

Each subject acts as their own control (reducing error variance - making test more sensitive)

Question 3

Disadvantages of RMA?

Answer 3

ORDER EFFECTS (learning or fatigue) - can compensate by counterbalancing

Differential CARRYOVER effect (can only combat by going to between subject)

Question 4

Explain the key influence of variance in RM?

Answer 4

We can pull out and explain a larger amount of variance in RM and therefore have a smaller error term (easier to identify sig)

Question 5

What is an additional assumption of RM?

Answer 5

Sphericity

Question 6

What is sphericity?

Answer 6

It requires the variance of the differences between each of the levels to be the same

Question 7

When is Sphericity always met?

Answer 7

When there is only two levels of an IV - more levels means not met almost always

Question 8

What happens when sphericity is not met?

Answer 8

The anova becomes too liberal/generous at identifying differences as significant (calling sig when its prob not)

Question 9

What do we do if sphericity has been violated?

Answer 9

We need to correct for it by adjusting the degrees of freedom in the F stat by a correction factor. - done with GG

Question 10

What test is there to determine whether you need to make a epsilon correction?

Answer 10

Mauchly (p value greater than 0.05 means sphericity has been met)

Question 11

What do n2 and n2p represent?

Answer 11

The variation %

Question 12

What is the main thing that counterbalancing does?

Answer 12

Distributes the effects of RM equally across conditions

Question 13

What is a limitation of counterbalancing?

Answer 13

We are limited to sample sizes that are multiples of the possible number of orders

Question 14

Why would we avoid counterbalancing for large sample sizes?

Answer 14

It would undermine the benefit of having RM

Question 15

Benefit ot latin designs?

Answer 15

More economical as they counterbalance using a selection of possible orders rather than all possible orders

Question 16

What are the 2 conditions of latin squares?

Answer 16

1: each treatment occurs equally often in each position in the treatment order.
2: each treatment immediately precedes and immediately follows each treatment exactly equally often

Question 17

Once produced a latin square, what can you do?

Answer 17

You can just use it to obtain the sequences for presentation of treatment conditions to participants (eg just use it to counterbalance)

Question 18

What is a downfall of latin squares?

Answer 18

Can only be used if sphericity is met